Control atmosphere for gas sampling apparatus



R L. BAILEY 3,449,958 CONTROL ATMOSPHERE FOR GAS SAMPLING APPARATUS June17, 1969 Sheet Filed April 25, 1966 I NVENTOR.

MOLECULAR 9051977 A 19/4/15) BY/ M m June 17, 1969 R. L. BAILEY3,449,958

CONTROL ATMOSPHERE FOR GAS SAMPLING APPARATUS Filed April 25, 1966 Sheet2 012 INVENTOR. ROBERT L. Ell/LE Y BY 'M Z M MW ATTYS.

United States Patent 3,449,958 CONTROL ATMOSPHERE FOR GAS SAMPLINGAPPARATUS Robert L. Bailey, Spokane, Wash., assignor to NationalDistillers and Chemical Corp., New York, N.Y., a corporation of VirginiaFiled Apr. 25, 1966, Ser. No. 544,778 Int. Cl. G01n N22 US. Cl. 73-42153 Claims ABSTRACT OF 'THE DISCLOSURE This invention relates to anapparatus to provide a control atmosphere to an atmospheric samplingdevice for purging the device of contaminated air between successivetests. It also provides a reference atmosphere of known controlledquality to insure accuracy in testing procedures.

This invention relates to an improvement in a device for samplingatmosphere within successive containers to detect the presence oforganic vapors or other gases indicative of contamination within thecontainers. An example of such an apparatus is described fully in myprior patent 3,266,292 granted August 16, 1966. Generally, the apparatuscomprises an atmosphere sampler having an inlet through which atmosphereis withdrawn from a container, the inlet of the sampler being movablebetween a first position at which the atmosphere is removed from acontainer and a second position wherein the inlet of the sampler isclear of atmosphere from within the container. The sampler can includeany type of detection cell or device for monitoring the quality ornature of the atmosphere sample. The present invention adds to thisbasic combination a source of control atmosphere and a device to insurethat the control atmosphere is directed to the inlet of the sampler whenthe sample inlet is in its second position clear of atmosphere withinthe container. The use of the control atmosphere provides a knownatmosphere reference for balancing and otherwise calibrating thedetection cell and associated equipment. It also assists in purging thesampler and associated atmosphere testing devices between successivetests, so that the devices can be recycled and used efiectively to testthe atmosphere from within successive containers.

It is a first object of this invention to provide a mechanism fordirecting a control atmosphere to a sampler inlet movable between atesting position and a position clear of the atmosphere being sampled.

Another object of this invention is to provide a device for directingcontrol atmosphere to an atmosphere sampling inlet during intermittentperiods in which the inlet is not being used to draw atmosphere samplesfor testing purposes, the provision of control atmosphere betweentesting cycles being automatic and requiring no monitoring oroperational controls.

Another object of this invention is to provide a curtain of controlatmosphere about the inlet of an atmosphere sampler between successivetests to enable the sampler and associated devices to be recycledbetween tests and to be calibrated or balanced when necessary.

These and further objects will be evident from the following disclosuretaken also with the accompanying drawings, the drawings illustrating apreferred form of the invention. It is to be understood that this formof the invention is only presented by way of examples and that variousmodifications may well present themselves to one skilled in this artwithout deviating from the concepts basic to this development. For thisreason, the two physical forms of this device shown in the drawings arenot to limit the scope of the claimed invention.

In the drawings:

FIGURE 1 is a schematic diagram showing the basic components of thecombination including the sampler apparatus and the apparatus forproviding control atmosphere to the sampler between tests;

FIGURE 2 is an enlarged fragmentary vertical sectional view through thesampler and stationar hood shown in FIGURE 1, further illustrating therelative positions of containers being tested;

FIGURE 3 is a bottom view of the atmosphere handling apparatus as seenalong line 3-3 in FIGURE 2;

FIGURE 4 is a vertical sectional view taken through a second form of thedevice illustrating alternate positions thereof; and

FIGURE 5 is a top view of the control atmosphere delivering element seenalong line 5-5 in FIGURE 4.

FIGURE 1 illustrates the basic combination of device used in samplingatmosphere from within successive containers to determine the presenceof contaminating organic vapors or gases inside the container. Thedevice is desirable or necessary in testing containers prior toutilization of the containers for sale or storage of food products, suchas milk. The testing procedure is preferably carried out immediatelyprior to filling of the containers. The atmosphere testing deviceincludes a detector 10 of a type adapted to monitor atmosphere directedthereto and to indicate the presence of organic vapors and otherundesirable gases in the sample atmosphere. The detector 10, as anexample, might include a vacuum pump or be connected to a source ofvacuum pressure to draw atmosphere through detector 10 for testingpurposes. As shown, detector 10 is connected by means of a tube 11 to atubular sampler 12. The sampler 12 has a lower inlet 12w through whichatmosphere is drawn for removal and delivery to the detector 10 throughtubing 11.

The tubular member 12 is selectively movable by conventional mechanicaldevices (not shown) between a first position wherein the lower inlet ofmember 12 can receive atmosphere from within a container 13 and a secondposition wherein the lower inlet 12a of member 12 is clear of atmospherewithin container 13. The first position of member 12 is shown in dashedlines in FIGURE 1, the second position being shown in full lines.

Vacuum is constantly applied to the inside tubular member 12. Member 12is successively inserted within or placed in close proximity to theinterior of containers 13. Atmosphere will be drawn from each container13 for testing by detector 10. After removal of the inlet of sampler 12from close proximity to the interior of container 13, it is desirable toprovide a control or known sample of atmosphere to the inlet of member12 so as to purge detector 10 of any trace of contamination betweensuccessivetests. This is the primary purpose of the apparatus describedbelow.

In the first form of the invention, FIGURES 2 and 3, an air curtain isprovided about the inlet of the tubular member 12 when such inlet is inits upper position and clear of atmosphere within the container 13. Asshown, this air curtain is provided within a semi-enclosed member 15having an aperture 16 closely surrounding the exterior of tubular member12 and permitting member 12 to slide freely therein. The member 15includes an inverted chamber 17 to which the control atmosphere isdirected by means of a port 18.

The desired control atmosphere is provided by a conventional pump 20having its inlet connected to the exterior atmosphere in the environmentwithin which the sampling device is used or to any other suitable sourceof air or gas. This connection is effected through a molecular sieve orother filter devices which remove contaminants from the air drawn bypump 20. The discharge from pump 20 is directed to port 18.

The volumetric flow of atmosphere from pump 20 and sieve 21 to thechamber 17 should be greater than the volumetric rate of flow ofatmosphere through the inlet 12a of tubular member 12. The excess airdirected into the chamber 17 therefore provides positive pressure aboutinlet 12:: to further prevent other atmosphere from entering the inlet1201 While inlet 12a is located within chamber 17.

This form of the invention is particularly simple, since it includes nomoving parts. The member 15 can be located in a fixed position upon theframe that it slidably supports tubular member 12 for movement relativeto the containers 13 as they are being tested. The pump 20 is preferablyoperated continuously during use of the testing apparatus, so that thecontrol atmosphere will be directed into the inverted chamber at alltimes and hence the control atmosphere will pass into inlet 12a of thetubular member 12 except during actual testing of a container 13. Theuse of a constant supply of control atmosphere permits calibration orbalancing of detector 10 at any time during a testing procedure andinsures greater accuracy in the detection of contaminants. It furtherinsures the complete purging of the sampler and associated detectiondevices, particularly immediately following the detection of a highdegree of contamination within atmosphere drawn from a container.

A second form of apparatus for directed control atmosphere to the inlet12a of the tubular member 12 is shown in FIGURES 4 and 5. There isprovided a tubular member pivotally mounted at 26 to a frame 22 thatmovably supports member 12. Tubular member 25 in the full line positionof FIGURE 4 intersects the path of movement of the tubular samplermember 12. Tubular member 25 is provided with a discharge opening 23 influid communication with a flexible connecting hose 24 operativelyconnected to the pump 20 and molecular sieve 21 or other suitable filteras previously described. The upper surface of member 25 at the endadjacent to the tubular member 12 is recessed slightly at 27 to seat thelower end of member 12 and therefore substantially seal the inlet 12aand discharge opening 23 when the members 12 and 25 are in the positionsshown in full lines in FIGURE 4. Member 25 is biased to this sealingposition by means of a counterweight 28. Obviously a spring biasingarrangement can be substituted in place of weight 28, or the location ofpivot 26 can be shifted to provide the necessary unbalance along thelength of member 25.

As seen in FIGURE 4, downward movement of member 12 will simply pivotthe member 25 about its pivotal connection 26, permitting the member 12to pass freely by the adjacent end of member 25. The slight contactpressure between member 25 and tubular member 12 does not in any mannerimpede the normal movement of the tubular member 12. The member 25 willreturn to its horizontal position with discharge opening 23 adjacent tothe inlet 12a of the sampler apparatus after completion of the testingcycle. Again, excess air should be supplied from pump 2.0 to insure thatall air received through the tubular member 12 between successive testsis of the quality known to be available through the molecular sieve 21.

Having thus described my invention, I claim:

1. In combination with an apparatus for withdrawing a sample ofatmosphere from a container by means of a sampler having an inletsubjected to a constant vacuum pressure, the inlet of the sampler beingmovable from a first position at which atmosphere from a container iswithdrawn thereby and a second position clear of atmosphere within thecontainer, the improvements comprising; the sampler being movablymounted on a supporting framework; a source of control atmosphere; anddelivery means to direct atmosphere from the source to the sampler inletwhen the inlet is located at the second position, the delivery meansincluding a member movably mounted on the frameworks in operativecontact with the sampler, said member having a discharge opening beingadjacent to and directed toward the inlet of the sampler when thesampler is located at said second position.

2. In combination with an apparatus for withdrawing a sample ofatmosphere from a container by means of a sampler having an inletsubjected to a constant vacuum pressure, the inlet of the sampler beingmovable between a first position at which atmosphere from within acontainer is withdrawn thereby and a second position clear of atmospherewithin the container, the improvements comprising the sampler beingmovably mounted on a sup porting framework; a source of controlatmosphere; and delivery means to direct atmosphere from said source tothe sampler inlet when the inlet is located at said second position,said delivery means including a surrounding member positioned about thesampler defining a semi-enclosed chamber about the sampler inlet whenthe sampler is in the second position, said delivery means including acontrol atmosphere exit directed toward the interior of the chamberfound within said member.

3. In combination with an apparatus for withdrawing a sample ofatmosphere from a container by means of a sampler having an inletsubjected to a constant vacuum pressure, the inlet of the sampler beingmovable between a first position at which atmosphere from within acontainer is withdrawn thereby and a second position clear of atmospherewithin the container, the improvements characterized by; the samplercomprising a hollow tubular member mounted on a supporting framework forreciprocal motion parallel to the axis of the tubular member; a sourceof control atmosphere; and delivery means to direct atmosphere from saidsource to the sampler inlet when the inlet is located in its said secondposition, said delivery means including a hollow member open at one endand surrounding the tubular member along a portion of the lengththereof, there being a discharge opening for delivery of controlatmosphere to the interior of the ho]- low member.

References Cited UNITED STATES PATENTS 3,266,322 8/1966 Negersmith etal. 73-423 FOREIGN PATENTS 954,067 4/ 1964 Great Britain.

S. CLEMENT SWISHER, Primary Examiner.

US. Cl. X.R. 73l

